A number of intravascular procedures are currently utilized to treat a stenosis within a body vessel of a human being. A common intravascular procedure is referred to as percutaneous transluminal coronary angioplasty (hereinafter “angioplasty”). During a typical angioplasty procedure, a guidewire is initially positioned within the body vessel and a guiding catheter is positioned over the guidewire. Next, a balloon catheter having an inflatable balloon is advanced through the guiding catheter and vessel until the balloon is adjacent to the stenosis. Subsequently, inflation of the balloon compresses the stenosis and dilates the body vessel.
During many surgical and clinical procedures it is necessary to determine the location or position of the catheter within the body of the patient into which it has been inserted. One manner of locating the position of the catheter is to add a sufficient amount of a radiopacifying agent directly to the polymeric catheter materials. Alternatively, the use of filler material in the polymer itself may be minimized, while building in wires or selectively placing metal bands that are highly radiopaque (see, for example U.S. Pat. Nos. 4,657,024 and U.S. Pat. No. 4,796,637, each of which is incorporated herein by reference in its entirety). Use of these types of catheters, however, has drawbacks. The metal bands, for example, are inherently very stiff and generate undesirable transitions in the flexibility of the catheter shaft. In addition, radiopaque wires are more costly than the commonly used stainless steel and, for simplicity in fabrication, such wires typically extend the full length of the device.
Thus, there is a need to develop a catheter that is easily visualized during its use in a patient without sacrificing the flexibility that is important during the use of the catheter. Similarly, there is a need for a catheter that may be visualized without substantially increasing the cost. A catheter that is flexible and visible under fluoroscopy or x-ray will enable people in the medical community to better perform surgical and clinical procedures involving a catheter. The present invention is directed to these, as well as other, important needs.